High-throughput screening of Mucoromycota fungi for production of low- and high-value lipids

Abstract

BackgroundMucoromycota fungi are important producers of low- and high-value lipids. Mortierella alpina is used for arachidonic acid production at industrial scale. In addition, oleaginous Mucoromycota fungi are promising candidates for biodiesel production. A critical step in the development of such biotechnological applications is the selection of suitable strains for lipid production. The aim of the present study was to use the Duetz-microtiter plate system combined with Fourier transform infrared (FTIR) spectroscopy for high-throughput screening of the potential of 100 Mucoromycota strains to produce low- and high-value lipids.ResultsWith this reproducible, high-throughput method, we found several promising strains for high-value omega-6 polyunsaturated fatty acid (PUFA) and biodiesel production purposes. Gamma-linolenic acid content was the highest in Mucor fragilis UBOCC-A-109196 (24.5% of total fatty acids), and Cunninghamella echinulata VKM F-470 (24.0%). For the first time, we observed concomitant gamma-linolenic acid and alpha-linolenic acid (up to 13.0%) production in psychrophilic Mucor flavus strains. Arachidonic acid was present the highest amount in M. alpina ATCC 32222 (41.1% of total fatty acids). Low cultivation temperature (15 °C) activated the temperature sensitive ∆17 desaturase enzyme in Mortierella spp., resulting in eicosapentaenoic acid production with up to 11.0% of total fatty acids in M. humilis VKM F-1494. Cunninghamella blakesleeana CCM-705, Umbelopsis vinacea CCM F-539 and UBOCC-A-101347 showed very good growth (23–26 g/L) and lipid production (7.0–8.3 g/L) with high palmitic and oleic acid, and low PUFA content, which makes them attractive candidates for biodiesel production. Absidia glauca CCM 451 had the highest total lipid content (47.2% of biomass) of all tested strains. We also demonstrated the potential of FTIR spectroscopy for high-throughput screening of total lipid content of oleaginous fungi.ConclusionsThe use of Duetz-microtiter plate system combined with FTIR spectroscopy and multivariate analysis, is a feasible approach for high-throughput screening of lipid production in Mucoromycota fungi. Several promising strains have been identified by this method for the production of high-value PUFA and biodiesel.Electronic supplementary materialThe online version of this article (10.1186/s13068-018-1070-7) contains supplementary material, which is available to authorized users.

Microcultivation and FTIR spectroscopy-based screening revealed a nutrient-induced co-production of high-value metabolites in oleaginous Mucoromycota fungi

“…lipid bodies) predominantly in the form of triacylglycerides (TAGs) [8,9]. Depending on a fungal strain, fungal lipids can be very similar to vegetable oils and thus suitable for biodiesel production, or similar to highly nutritious and valuable fish oils with high content of polyunsaturated fatty acids (PUFAs) [10][11][12][13]. Although SCOs production by oleaginous Mucoromycota fungi has been suggested and up-scaled a century ago [14], industrial process based on Mucoromycota fungi are still limited only to production of high-value PUFA-rich oils.…”

“…Moreover, FTIR spectroscopy was applied as a tool for measurement of growth media and extracellular metabolites [54,55]. FTIR spectroscopy has been shown to be precise and reliable method for the identification and analysis of microbial lipids [10,[56][57][58][59][60][61], chitin/chitosan [62][63][64][65] and polyphosphates [66,67]. Further, this method has been utilized for monitoring lipid extraction in oleaginous filamentous fungi [68,69].…”

“…Thus, FTIR showed the potential to serve as the sole method for the bioprocess monitoring. Combined with the Duetz microtiter plate system (Duetz-MTPS), FTIR can serve as a rapid tool for monitoring of high throughput studies, such as screening of fungal strains for high and low value lipid production [10,70]. Moreover, high throughput screening was strengthen by a fully automated set-up of the biomass samples preparation for the FTIR-HTS analysis [71][72][73].…”

Extended multiplicative signal correction for FTIR spectral quality test and pre‐processing of infrared imaging data

“…While the amide I and II bands from proteins dominate the infrared spectra of bacterial cells, carbohydrates and lipids are present in high concentrations in yeasts and fungi. For example, spectra from oleaginous fungi reveal bands of lipids that are much stronger than bands from proteins . Fungi (filamentous fungi and yeasts) have in general different morphologies and therefore different spectral characteristics influencing the quality of the spectra.…”

“…An FTIR spectrum represents a high-dimensional and reproducible molecular "fingerprint" of the chemical composition of biological cells and tissues containing characteristic signals from cell lipids, proteins, nucleic acids and carbohydrates [10,11]. FTIR spectral fingerprints combined with multivariate spectral analysis is therefore used frequently for the characterization and identification of microbial cells and tissues [6,[12][13][14][15][16][17][18].…”